Wireless Video Camera Transmit Distance

[Victor43]

Dear Readers.

I am interested to learn what factors influence transmission distance indoors where there are obstructions between transmitter and receiver. We have one project where we need to install a few wireless video cameras inside an old four story building. The distance between transmitter and receiver is about 100m. However there are several walls and floors made of concrete between transmitter and receiver. What role does the Transmit Power Output of the transmitter play ? Higher the better ? Also same for the antenna for the receiver ? The antennas for the transmitter will be omni directional. To the best of my knowledge the communication will be PTMT where we will have more then one monitoring station for the same set of video cameras. The highest TPO permitted which can use be used for the 1.5GHz band is 4W or 4000mw. What about using a repeater to achieve the distance we need ? We may have multi receivers hence the reason for omni directional transmitter antenna. Please note that these wireless video cameras have a small footprint and the transmitter will have its own PCB but enclosed in the same housing as of the camera so not separate.

Any comments or suggestions are welcome. Thanking you

Victor

 

[jiripolivka]

Dear Readers.

I am interested to learn what factors influence transmission distance indoors where there are obstructions between transmitter and receiver. We have one project where we need to install a few wireless video cameras inside an old four story building. The distance between transmitter and receiver is about 100m. However there are several walls and floors made of concrete between transmitter and receiver. What role does the Transmit Power Output of the transmitter play ? Higher the better ? Also same for the antenna for the receiver ? The antennas for the transmitter will be omni directional. To the best of my knowledge the communication will be PTMT where we will have more then one monitoring station for the same set of video cameras. The highest TPO permitted which can use be used for the 1.5GHz band is 4W or 4000mw. What about using a repeater to achieve the distance we need ? We may have multi receivers hence the reason for omni directional transmitter antenna. Please note that these wireless video cameras have a small footprint and the transmitter will have its own PCB but enclosed in the same housing as of the camera so not separate.

Any comments or suggestions are welcome. Thanking you

Victor

Typical "wireless cameras" utilize a FM transmitter with some 10 mW output and a sensitive FM receiver. Both have small patch or rod antennas and promise ranges of up to 30 m (100 ft.)

The simplest way to extend system range without circuit modification is to use higher-gain antennas. You can start with a 30-cm aluminum parabolic dish, put the transmitting patch in the focus and see how far away you can get a good picture. The dish may add ~10 dB gain. If you use another dish at the receiver, I think 100 meters can be achieved.

Instead of a dish you can try a 2.45 GHz Yagi, with 7-9 dB gain. Or make a corner reflector from hard paper and glue aluminum foil (reynolds wrap) to make it reflective.

Modifications to the transmitter to increase output power are possible but you need a well equipped lab to do it. Receiver is quite sensitive by design, barely offering any improvement.

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For your path with obstacles I would rather consider installing a coaxial cable to send the signal. Such cable helps to get around obstacles and its cost is low.

 

[Victor43]

Typical "wireless cameras" utilize a FM transmitter with some 10 mW output and a sensitive FM receiver. Both have small patch or rod antennas and promise ranges of up to 30 m (100 ft.)

The simplest way to extend system range without circuit modification is to use higher-gain antennas. You can start with a 30-cm aluminum parabolic dish, put the transmitting patch in the focus and see how far away you can get a good picture. The dish may add ~10 dB gain. If you use another dish at the receiver, I think 100 meters can be achieved.

Instead of a dish you can try a 2.45 GHz Yagi, with 7-9 dB gain. Or make a corner reflector from hard paper and glue aluminum foil (reynolds wrap) to make it reflective.

Modifications to the transmitter to increase output power are possible but you need a well equipped lab to do it. Receiver is quite sensitive by design, barely offering any improvement.

- - - Updated - - -

For your path with obstacles I would rather consider installing a coaxial cable to send the signal. Such cable helps to get around obstacles and its cost is low.

Thank you for your reply. All the points are well taken and clearly understood especially about the high gain antennas.
Victor